Ritsuko Nakajima is the mother of Youko Nakajima. Ritsuko is a well-meaning mother who, despite her stern demeanor, cares deeply about her daughter. Even though she has personal preferences, such as which schools she wants Youko to attend, she generally adheres to her husband's decisions as a dutiful wife. Concerned that Youko might stand out or be mistaken for a delinquent due to her naturally reddish hair, Ritsuko often advises her to cut it or dye it black.
When Youko is suddenly taken to the Twelve Kingdoms, her fate becomes unknown to those back home. Through visions brought on by the Suiguutou, Youko learns how her parents have reacted to her disappearance. Her mother expresses worry and fear, hoping Youko will return and refusing to believe that she ran away out of rebellion or was involved in an incident leading to her likely death. This causes tension in Ritsuko's relationship with her husband, as she resents his apparent lack of concern over Youko's disappearance. Over time, Ritsuko becomes more resigned to the idea that Youko was not as she seemed, influenced by others suggesting children are often not as they appear.
In the anime, Ritsuko eventually learns of Youko's fate from Yuka Sugimoto upon her return from the Twelve Kingdoms. Though saddened that Youko will not come back, she finds comfort in knowing Youko is doing well where she is. In the novels, it remains unknown if Ritsuko ever learns what became of Youko.
